Automatic telephone system



May27, 1930. H. M. FRIENDLY AUTOMATIC TELEPHONE SYSTEM Filed March 19.1928 7 Sheets-Sheet Inverdur- Herbert-P'I-fiiendl May 27, 1930. H. M.FRIENDLY AUTOMATIC TELEPHONE SYSTEM Filed March 19. 1928 7 Sheets-SheetEIIU May 27, 1930. H. M. FRIENDLY 1,760,823

- AUTOMATIC TELEPHONE SYSTEM Filed March 19. 1928 7 Sheets-Sheet 3 May27, 1930. H. M. FRIENDLY AUTOMATIC TELEPHONE SYSTEM Filed March 19. 19287 Sheets-Sheet M90, PM u F knrmukkkkmukk w vmN 1mm. I |UHHH o mww, M90.D

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AUTOMATIC TELEPHONE SYS TEM Filed March 19. 1928 7 Sheets-Sheet 5-Inven1ur- HErhEPi-PI-FriEindlg @aw A May 27, 1930. H. M. FRIENDLYAUTOMATIC TELEPHONE SYSTEM 7 Sheets-Sheet Filed March 19, 1928 mm W Ami

Patented May 27, 1930 meas es 1 rent HERBERT 1a. FRIENDLY, OF CHICAGO,ILLINOIS AUTOMATIC TELEPHONE sYs'rEM Application filed March 19, 1928.Serial No. 262,626.

The present invention relates to telephone systems; more particularlyso-called automatic or machine switching telephone systems.

' General objects I The general objects of the presentinvention are toenable a subscriber of the auto matic telephone system, who contemplatestemporarily leaving the location of his telephone, to directively setcentral ollice apparatus or call forwarding equipment associated withhis line through the agency of his automatic calling device dial on histelephone so that in case any calls are thereafter directed to his line,the latter said calls will be further extended or forwarded to apredetermined random subscribers line or other line of the system. Thatis, forexample, a subscriber before leaving the premises may remove thereceiver of his telephone as if to initiate a call, and then operate hiscalling device dial by placing his fore-finger in a spe cific depressionfinger-hold of the dial and then draw the dial until his fingerencounters the finger-stop, so that when the dial is released it willsend a series of eleven open impulses. After the dial has restored, hewill restore the receiver, leaving the central office call-forwardingequipment in the set conditicn.

To unset the said call-forwarding equipment, he will similarly operatethe dial from another specific finger-hold depression, so that when itis released it will send a series of twelve open impulses. After thedial has restored, he will restore the receiver, leaving the centraloilice call-forwarding equipment in the normal unset condition.

However, in accordance with the present invention, in the event that thebefore-mentioned (normally) predetermined line is not the line to whichit is in the particular instance desired to have the calls forwarded to,

the predetermined line may be directively changed. The latter isaccomplished by annexin the telephone number of the line to which it isdesired to have calls forwarded. to in the particular instance,forthwith after operating the dial to effect the series of eleven openimpulses mentioned. The receiver Wlll then be restored to theswitch-hook, leaving the set line in condition forforwarding callsdirected to it to the specific line indexed by the number annexed afterprimarily set ting the line by the series of eleven open impulses. Thatis to say, not only is there a normally predetermined line to whichcalls may be forwarded when a set condition exists on a line called, butthis normally predetermined line may be temporarily changed to a randomdesired line ofthe exchange.

In connection with the last foregoing, relating to changing from thenormally predetermined line to a random desired line to which callswillbe forwarded under the set condition, when the subscribers line isto be unset it is done by removing. receiver as in initiating a callthereon, and then sending a series of twelve open impulses. The latterelfaces not only the said set condition accomplished responsive to thefirst said sending of the eleven open impulses,but it also effaces thesubstituted random desired line and ma ders the normally predeterminedline subject to being called when the subscriber next causes his line tobe set by sending theseries of eleven open impulses and withoutannexingany digits,

It will thus be'perceived that the present invention is adapted for usein connection with a subscribers telephone line wherein it may bedesired to have calls which may be .made thereto, in the absence of thesubscriber, forwarded to a desired random line of the exchange as may bepredetermined by the subscriber when he sets his line for forwardingcalls made thereto. That is, a residence subscriber may leave hisresidence and go to the residence of some other random subscriber, anddesires that all calls made to his tele phone be forwarded to thetelephone of the subscriber where he will be found. Moreover, a businessestablishment may wish to have some employee respond to after businesshours calls. The line will, therefore, be F set to forward calls made toit ,to' any desired telephone of an employee, perhaps a differentemployee being selected for succes sive days. That is, there may be apredetermined employee who will be charged with responding to such callsresponsive to the normal setting of the set relay, while this may atwill be changed to a random telephone line by simply annexing the numberof the latter telephone line, after normally setting the line forforwarding.

The set condition may be at will efi'aced. It will be effaced at apredetermined time automatically. Of course, a manual setting may bemade in the central office, in the event the subscriber neglected to setthe line, and a duly authenticated request from him is made for suchsetting.

General operation Reference is made to my pending applications forpatent Ser. No. 218,605, filed Sept. 10, 1927; Ser. No. 241,793, filedDec. 22, 1927 Ser. N o. 257 ,480, filed Feb. 27, 1928, and Ser. No.259,047, filed March 5, 1928. These pending applications are directed totelephone systems and apparatus having objects broadly as set forth inthe foregoing statements. The present invention has features believed tobe novel but not disclosed in the said cited pending applications. Someof these latter said novel features will be specifically described andpointed out in the present specifications, while other said novelfeatures will be apparent in view of the disclosures specifically setforth in the specifications and drawings.

Among the features of the present invention believed to be novel are:

(1. Means whereby after the subscriber has caused his line to set forforwarding calls to the predetermined line by operating the callingdevice dial in accordance with the setting finger-hold, thereby sendinga series of eleven open impulses, he can again operate his callingdevice dial in accordance with the said finger-hold and thereby cause aconnection to be linked from the subscribers line now set to the saidpredetermined line. The response on the latter said line will verify theset condition of the subscribers line. The subscriber can then hang uphis receiver, leaving his line in the set condition, the said linkedconnection being at the same time destroyed.

6. Means whereby after the subscriber has caused his line to be set'forforwarding calls to the said predetermined line, he can thereuponoperate his calling device with correspondence to the digits of adesired random line of the exchange, and thereby change the primarysetting with respect to the said predetermined line to an arbitrarysetting for the random line indexed by the digits anneXed by the dialafter sending the series of eleven open impulses to set the subscribersline, and he can further thereupon again operate his calling device inaccordance with the said setting finger-hold and thereby causeconnection to be linked from his line to the said random line. Theresponse on the latter said line will verify the set condition ofthesubscribersline. The subscriber can then hang up his receiver,leaving his line in the set condition, the said linked connection beingat the same time destroyed.

a. Means whereby the operation set forth in paragraph b as tothe linkingof the call can be alternatively elfectuated responsive to sending anydigit from 1 to O in place of sending the series of eleven openimpulses.

d. Means whereby if a connection is caused .to be linked from thesubscribers line, as set forth in paragraphs a, b, and 0, when theresponse occurs on the line to which the connection has been linked,andwhich is the line to which calls made to the subscribers line will beextended, when the response occurs the direction of current traversingthe receiver on the subscribers line will be reversed in direction. Thisreversing of current may control supervisory signals or meter orcoin-box toll devices, it being old in the art to control such devicesby current reversal. However, it is believed that the means disclosed bythe present invention for accomplishing this reversal is novel. 7

6. Means whereby the unsetting of the set condition of the setsubscribers line can be effaced by sending a series of twelve openimpulses efi'ectuated by operating a specific finger-hold'on the dial ofthe calling device, which latter said finger-hold is located next to thesetting finger-hold for sending a series of eleven open impulses. Thismeans includes off-normal springs on the first se-" lector operated atthe eleventh and twelfth levels when the wipers rotate-in on therespective levels. The eleventh level said offnormal springs cause minusbattery to be applied over an operating conductor to effect the said setcondition. The twelfth level said off-normal springs cause plus batteryto be applied over said operating conductor to effect the effacement ofthe said set condition. The said operating conductor leads through thewinding of a polarized relay to ground, so that the armature of thelatter said relay will operate to close a ground path to a specificoperating conductor for setting and a specific said conductor forunsetting, depending upon if minus or plus battery is applied over thesaid operating conductor responsive to the operation of the dial forsetting or unsetting.

f. An impulse sending mechanism is shown (Fig. 5)- that is common to aplurality of subscribers lines, as distinct from the impulse insure thatonly the testing Wiper will bear appreciably on its co-operating bankterminals to effect conductive relation, while the remaining wipers'willeither remain out of conductive engagement with co-operative This deviceincludes a shaft (Fig. 8) with a slip coupling and a magnet forattracting the shaft, andall wipers excepting the said test wiper,endwise wherein the said coupling will permit the shaft to move endwisewithout affecting the tension between the test wiper and itsco-operative bank terminal it is then resting upon.

Drawings With reference to the accompanying drawings Fig. 1 shows acalling telephone A leadingin to a line switch B. It also shows a setrelay 0 for changing the so-termed normal conductors from the lineleading to the line switch B to the corresponding terminals accessiblefrom line finder switch F in Fig. 8. Theindicated connector D normallyhas access to the line leading to telephone A.

Fig. 2 shows a first selector E of a group accessible from line switchB. It also indicates a calling telephone A leading to a line switch Lthe latter having access to first selector B second selector C thirdselector J and connector D in Fig. 1 in sequence, to complete a callfrom telephone A in Fig. 2 to the telephone A in Fig. 1.

Fig. 8 shows a line finder switch F involving auxiliary apparatus, thesaid switch having access to terminals of a plurality of lines which maybe called through connector D inFig. 1, or random connectors in theexchange oiiice containingconnector D wherein contact springs of a setrelay similar to relay 0 are interposed. Each said line accessible fromthe switch'F has a line relay as shown on the left aligned with therelays of the said switch. l'Vhen the switch F operates and seizes a setof its bank terminals corresponding to a line called, its lower group offifteen wipers are then co-operative with bank terminals whichcorrespond to the line to which said set relay 0 belongs. The saidswitch F has an impulse sending mechanism individual to it and shown inFig. 5. i

.Fig. 1 shows a first selector G companion to and individual to theswitch F in Fig. 3. The

3 first selector Ghas access to other switches in common with firstselectorE in Fig. 2.

the digit setting switches for the first three digits of the number (offive digits) of the line to which calls directed to theline leading totelephone Aare topbe forwarded to.

Fig. '7 shows switches K and L, being the digit setting switches for thelast two digits of the number of the line to which" calls directed' tothe line leading to telephone A are to be forwarded to. Fig. 7 alsoshows the switch M which distributes to the switches H to L. V r

Fig. 8 shows the details of the wiper shaft for switch F in Fig. 3,referred to inthe fore- 7 going paragraph A.

Fig. 9 shows a'preferred modification of the switch H in Fig. 6.

Fig. 10 shows the dial of the sending device of the present invention.This dial is generally like the dial disclosed in Figs. 7 and 8 of mysaid pending application Ser. No. 218,605, filed Sept. 10, 1927.However, the dial of the present invention has an added finger held Yfor sending a series of twelve open impulses. V

Fig. 11 isa diagram showing the assembly of the seven sheets ofaccompanying drawings-to disclose the circuits employed to e emplify thepresent invention. The lines extending towards the margins whichregister are cent-inuations of the same line.

Equipment The telephone A in Fig. 1 is the well known common batteryseries type, but is equipped with an automatic calling device and dialas disclosed in Fig. 10. This dial, responsive to operating it inaccordance with one of the two finger-hold depressions Z or Y will senda series of eleven or a series of twelve open impulses, respectively,depending upon which finger-hold is operated.

The line switch B is of the well known rotary class as described on page'53 of Hersheys Automatic Telephone Practice, third edition. However,the line switch B has an added wiper for the objects of the presentinventlon. I

The connector D in Fig. 1 is of the well known type as shown in Fig. 7 3of the fourth edition of the said book.

The first selector E in Fig. 2 is of the well known type sometimescalled a Powell se-. lector, and described on pages 59 to 61 of the saidthird edition of Hersheys book.

However, two sets of off-normal springs, which respectively operate onin positions on the eleventh and twelfth'bank levels,an'd connectedcircuits, have been introduced for the purposes of the presentinvention. It also has twelve levels'of bank terminals.

The first selector G in Fig. 4 is of the well known said Powell type.

The selectors B C D E F and J in Fig. 2 and D in Fig. 4 are likeselector G in Fig. 4.

The line switch L in Fig. 2 is like switch B in Fig. 1.

The connectors H and G in Fig. 2 are like connector D in Fig. 1.

The line finder switch F in Fig. 3 is of the class shown and describedon pages 55 to 57 of the third edition of Hersheys book. How- 7 ever, itis modified for the purposes of the present invention.

The switch elements R and S in Fig. 5, and the switch elements H, I andJ in Fig. 6, and the switch elements K, L and M in Fig. 7, belong to theclass of switch 13 in Fig. 1, modified in accordance with the presentinvention.

It will be understood that any other suitable switches may besubstituted for the said well known switches mentioned, withoutdeparting from the spirit of the present invention. Also, that theswitches specific to the present invention may be modified by thoseskilled in the art without departing from the spirit of the presentinvention, as defined by the subjoined claims.

It will, of course, be understood that in a commercial embodiment of thepresent invention a plurality of switches in a group will be employed inplace of the exemplary single switches used in disclosing the presentinvention, so that a plurality of calls may be co-existent, the switchesin the groups having predetermined order. of use with respect toantecedent co-operative switches.

Detailed 0pemli0nnitatlng a call from telephone A to telephone A D and Fand connector H The connection may then be released in the well knownmanner, responsive to the calling party replacing his receiver on theswitch-hook. A call to telephone A the telephone number of which is14321, will be effected in a generally like manner. It will be notedthat the telephones A andA are both located tributary to the 1 olfice ofthe exchange, reached through the 1 level of first selector E. Of

course, other telephones of the system (not indicated) may be reachedthrough other levels of the selector E, and, therefore, belong tocorresponding oflices of the exchange. Thus, outgoing calls fromtelephone A under normal conditions are made in the well known manner,and employ well known switches,

with due regard to the special modifications Setting the'line leading totelephone A so that calls directed to said line will be forwarded totelephone A Let it be assumed that the party at telephone A desires toset his line so that calls directed thereto will be forwarded totelephone A. The party at telephone A will remove his receiver as if toinitiate an ordinary call. This will cause the line switch to operateand select a firstfselector as E. The party at telephone A will thenoperate his callingdevice dial, Fig. 10, in accordance with the specialfinger-hold depression Z to effect a series of eleven open impulseswhich will step the shaft of selector E-vertically in accordancetherewith and operate the eleventh vertical off-normal springs 201. Thelatter operation will cause the indicated plus battery to be appliedover conductor 202,

bank terminal 12 of set 12 to 15, wiper 16 of set 16 to 19, armature 20,winding of polarized relay 21 to ground, the armature 22 applying groundthrough armature 23 to the winding of relay 24, the latter said relayactuating. The relay 24 will thus remain actuated as long as the groundis maintained by armature 22.

At the time the off-normal springs 201 operated, the selector E operatedin the well known manner to rotate-in and seize by its wipers 205 to 207the first set of idle bank terminals 208 to 210 on the eleventh level.The latter said set will be the ones corresponding to slow-releasingrelay 212. The latter said relay will operate responsive to the seizingby selector E when its relay 213 actuates, and ground from armature 214will be applied through bankterminal 208, wiper 205, armature 215,release trunk conductor 216, bank terminal 13, wiper 17, armature 26,conductor 27. This ground to the release trunk will, therefore, maintainthe relays 213 and 28 actuated as long as the windings of relay 212 aremaintained energized through telephone A by the party thereatmaintaining his receiver off the switch-hook. The plus battery fromsprings 201 is similarly maintained to the winding of relay21 until theshaft of selector E is restored under control of the party attelephoneA.

At the time relay 24 actuates, its armature 30 disconnects the windingof relay 31. Armature 25 at the same time applies ground received fromarmature 22 to the winding of magnet 34 of the set relay 0. The lattersaid magnet will cause the springs of relay C to be operated and the dog35 latched over the catch 36 to retain the springs of relay G operatedafter the winding of magnet 34 has been deenergized.

When the party at telephone A now hangs up his receiver, the relay 212will deenergize and remove the ground from the release trunk 216, andthus cause the shaft of selector E to be restored and the armature 22 toassume the drawn normal position, free of its co-operating contacts sothat the relay 24 -will'thereunon unlock the rela C hein in Unsette'ngthe line leading to telephone A so that calls thereafter directed tosaid line will not be forwarded therefrom, the said line then being innormal condition Let it be assumed that the party at telephone A desiresto unset his line, by unlocking the relay C and thus causing the springsthereof to restore to normal condition. The

party at telephone A will remove his receiver as if to initiate anordinary call, having in mind that even if the springs on relay C areoperated and locked by the dog 85, outgoing calls from telephone Athrough the line switch B will be effected normally as if the springs onrelay C were not in their operated condition.

The party at telephone A will then operate his calling device dial inaccordance with the special finger-hold Y depression to effect a seriesof twelve open impulses which will step the shaft of selector Evertically in accordance therewith and operate the twelfth verticaloff-normal springs 217 v and select the relay 212, which relay is, forconvenience, connected in multiple with the correspond ing verticallyaligning sets of the eleventh and twelfth levels. Thus, the relay 212was selected on the twelfth level in the same manner as it was selectedon the eleventh level when the relay C was set. In the present instancecurrent from the indicated minus battery is applied through the springset 217,

conductor 202 to operate relay 21 in the indicated minus direction, thearmature 22 applying ground through armature to the winding of relay 31,the latter said relay actuating: This latter energizing circuit willendure until the relay 21 1s deenergized by releasing the shaft onselector E.

At the time therelay 31--actuates,its armature 23 disconnects thewinding of relay 24. V

Armature 40 at the same time applies ground from armature 22 to thewinding of unlatching magnet 43 of the set relay C. This will on relay Cto restore to normal condition.

When the party at telephone A now hangs 7 up his receiver the relay 212willdeenerg'ize and remove the ground from the release trunk 216, andthus cause the shaft of selector E to be restored and the armature 22 toassume the drawn normal position, free of its co-operating contacts sothat the relay 31 will thereupon deenergize, the circuits being now atnormal;

Relay 0 2'8 locked and unlocked according to prearranged time scheduleThe time controlled circuit grounding device P and Q revolvecontinuously in the indicated direction at uniform speed, making arevolution in twenty-four hours. The conductive segment '46 appliesground received from brush 47 through brush'48, armature 49 to thewinding of slow-releasing relay 50, the latter said relay actuating at 5p.- In.

This is assuming that the drawn position of r the device Q, is at 12 p.m. The conductive segment 52 applies ground received from brush 53through brush 54,- armature 55-to the winding of sloW-releasingrelay 56,the

latter said relay actuatingat 9' p. Ii'l': This is assuming that thedrawn position of th device P is at 12 m. In view of theindicateddirection of revolution of the devicesP and Q, the device Qwill be the first one to applygroi'ind through its brush48. j This willoccur at 9 a. m.,as stated. Responsive to relay 5O actuating, relay 60will actuate and lockto ground on armature 49 until the ground appliedthrough brush 48 is removedbecauseof the segment 46 moving from underthe brush 48.

When relay 6O actuates, it deenergizesthe relay 50, and the latter saidrelay will'the'n deactuate consistent with its slow-releasingcharacteristic. Only during the shorttime that relay 50 is actuated,ground from armature 61 will be applied through armature 23 to thewinding of relay 24. The relay 24 will actuate in the manner beforedescribed to in turn cause the energization of magnet 34" from theground appliedfrom armature 61 through armatures 23 and 25, to operateand lock the springs on set relay C.v

At 9 a. nil following the operation of relay 50, ground will be appliedfrom brush 54 of device P'effective to operat'ethe relay 56.

Responsive to relay 56 actuating, relay 63- latter said relay willthen'rdeactuate consistent with its slow-releasingcharacteristic.Onlyduring the; short time that relay '56 is actuated, groundfromarmature64 will be 7 applied through armature 30 to the winding Therelay 31 will actuate in the of relay 31. V v manner before described toin'turn causethe.

energization of. the magnet 43 from the ground applied from armature 64through armatures 30 and 40, to disengage the dog 35 sothat the springsof relay C will restore to normal condition, and, therefore, the relayC. will be in its unset condition.

It will be particularly noted that if, for example, the relay C was inits set condition at the time relay 50 actuated, the relay 24 will becaused to actuate as before described to energize the winding of themagnet 34, but to no efiective purpose with respect to the set conditionof relay C. In the same manner, if the relay C is at normal and therelay 56 actuated, the relay 31'willbe caused to actuate as beforedescribed to energize the winding of magnet 43, but to no effectivepurpose with respect to the unset condition of relay C. 1 It will thusbe clear that while applying plus or minus battery over conductor 202will change the operative condition of relay C, the relays 50 and 56 canonlyset the relay C or unset it, respectively. Thus, if the party attelephone A has set the relay G at 4:45 p. m., and at 5 p. m.the relay50 operates, no confusion can occur. In the same manner, if the party attelephone A has unsetthe relay C at 8: 30 a. m. and at 9 a. 1n. therelay 63 operates, no confusion can occur. However, in the event thesubscriber through ,inadvertance fails to operate his set relay 0 beforeleaving for the night, the relay C will be automatically setat 5 p. m. V

In this connection it will be understood that there will be as manysetscorresponding to P and Q, and their individualxpair of re lays 56and 63, and 50 and 60, respectively, as there are times of the day whenset relays, as C, are to be operated, the various set relays beingassociated with the proper said device as P and Q depending upon thetime of day it is to be automatically set and unset. I

It willvbe noted that no confusion can arise by reason of more than onesetting or unsetting operation occuring. That is, by a secondpartyperforming a setting or unseting operation. a If two or more likeoperations are madesuccessively, only the first one will be operativelyefiective to the set relay-C.

Call to the line leading to telephone A under normal eonditionhuhereinthe relay is not set Assume that the party at telephone A debe operatedin accordance with digits 2.2- 21 1 after initiatingthecall, This willsuccessively operate the selectors B C and.

J and connector D so that wipers 65, 66, and

v 67 will seize bank terminals 71, 72, and 73, re-' spectively. beapplied overprivate wiper 65, bank ter- Ground from the connector willminal 71, spring 74 to the winding of relay at telephone A, in the Wellknown manner, the effective circuits being those well known fromHersheys book cited.

The connector D will now apply signaling current effective to the bellCall to the line leading to telephone A Wk,

der the condition that the set relay 0 is in operated condition Nowassume that at the time the wipers 65 to 67 are set upon the bankterminals 71 to 73, respectively, the set relay C is in its operated andlatched condition. Under the latter said condition, the relay 28 willnot be energized, since the normal conductors are disconnected fromrtheline leading to telephone A. However, the latter said condition does notprevent the party at telephone A normally extending calls from saidtelephone.

.It will be noted that the conductors leadin g from bank terminals 71 to73 disconnected from the line leading to telephone A are now connectedto conductors 75 to 77, respectively. Thus, when the connector D seizesthe line terminals 71 to 73, groundis applied from the connector overwiper 65, bank terminal 71, spring 74, conductor 75, armature 301,

' lower winding of relay 302, winding of common relay 303 to groundedbattery, the relay 302 actuating and causing the dependent common relay305 to actuate. Armature 306 on relay 302 will attract from'its restingcontact to its make contact, while armature 301 remains inert for thetime being. This condition causes all the bank terminals accessible fromthe wiper 311, of the group 311 to 313, to be grounded by the armature314 of relay 305, excepting the bank terminal 315, corresponding to therelay 302, due to the attracted condition of armature 306. Ground isapplied from the armature 314, conductor 317,

armature 318 to the winding of sl0w-releasing relay 319, the latter saidrelay actuating.

The armature 321 applies ground to the lower terminal of the winding ofrelay 323, while the ground on-the bank terminals successively engagedby wiper 311 is applied through armatures 324 and 325 to the-upperterminal of thewinding of relay 323. The lat ter said ground is alsoapplied through the interrupter armature of motormagnet 327 to thewinding thereof, the said motor magnet operating to' successively stepadvance the wipers 311 to 313.. When Wiper311 encounters bank terminal315 it will notv receive 3 ground because of the attracted condition ofarmature 306; so that the-short-circuit is re moved from the winding ofrelay 323 and the direct ground is removed from the winding of the motormagnet 327. Due to the marginal adjustment of the motor magnet, it willcease operating under the condition, but the The ground received overconductor lay 407.

V the latter said relay 302 at armature 301 and connects ground receivedfrom the connector D over conductor 75 through armature 301, bankterminal 315, wiper 311 to armature 324 to maintain the relay 323 lockedbefore the armature 321 has had time to retract. Th relays 303 and 305will now deactuate it there is no other relay like relay 302- withits/lower winding energized, due to a waiting call. It the relays 303 to305are actuator after relay 302 tully actuates, the ground applied overconductor 317 will be continued through armatures 318 and 330 to thearmature corresponding to 318 of the next finder switch like F (notshown) of the group of whichswitch F is' one.

i to the winding of relay 335, the latter said relay actuating.Resultant to the actuation of the relay 335a circuit path can be traced"from grounded battery, upper winding ot'relay 401, armature 402,conductor 403, armature 336, conductor 337, armatures 501 and 502 inmultiple, conductor 503, armature 338, conductor 339, armature 405,lower winding of relay 401 to ground, the latter said relay actuating,followed by slow-releasing release re- Ground will now be appliedthrough armature 408 to release trunk concuctor 409. Ground is appliedthrough armature 341, conductor 342 to' the winding of relay 505, thelatter said relay actuating. Ground will now be applied from armature506, wiper 509 of set- 507 to 509, bank terminal 510, bank terminal 511,wiper512 of set 512 to 515, bank terminal 516, armature 517 to thewinding of relay 518, the latter said relay actuating and appliedthrough armatures 331 and 334 locking through armatures 519 and 520 toground In this connection, it will be noted that the interrupter lrevolves at the rate. of approximately twelve times per second, so thatthe next ground impulse applied thereby will be to the windin of rela523 and throu h ar- 2 b y b that the latter said wipers are now. restingappliedthrough armature 521, armature. 522

mature 524 to the winding of motor magnet 525 or" switch R, the saidrelay 523 and magnet 525 coincidently operating. The wipers 512 to515w1ll thus 3e step advanced responsive to the groundings of theinterrupter T The armature 501 will attract coincident with the firstenergization of the motor magnet, the armature 502 of relay 526 willmaintain the relay 401 in selector G energized until the wiper 514encounters groundon the first oil normal'bank terminal co-operativetherewith,

"and, thereby, energizes relay 526 over an obtowa vious circuit path,after which time the relay 401 in selector G will be under the solecontrol of armature 501.

At the time armature 331 attracted, it applied ground to energize themagnet M. The latter said magnet will draw the portion of the shaftcarrying all the wipers excepting private wiper 315 so that, enoughpressure on tion 803 tits slidably in the sleeve 801 and car-v rise afixed pin 804 which may move along the slot 805. Thus the wipers on theportion of the shaft 803 rest lightly on the'bank terminals as they arerotated by the shaft section with which the motor magnet 327V 00-operates. Then when the magnetM is enerthe section of the shatt803 willbe drawn rds the magnet M and the pin 804- will change itspositionaccordingly, while all the w"; ers on the section 803 will rotate withsection 802 wherein the pin 804 is a link between said sections 802 and803. The shaft is journaled in bearings 806. Y

Bank terminals 510, 527 to 530 of switch S are respectively tied byconductors to wipers to 347 on the shaft 803 oi the switch F.

t will also be noted thatthe latter said wipers are now resting uponbank terminals 351. to which align with bank terminal 315; That is tosay, the bank terminals 351 to 355 of switch F are individual to theline leading to telephone A.

The said bank terminals 351 to 355 are respectively tied by conductorstowiper 601' of set 601 to 603 of switch l-l; wiper 604 ot'set 604 to 606of switch I wiper 607 of set 607 to 609 of switch J wiper 701 of set701to 703 of switch K; wiper 704 of set 704 to 706 of switch L. i

Bank terminals 531 to 540 are respectively tied by conductors to wipers356 to 365 on the shatt 803 or" switch F. It will also be noted uponbank terminals 366 to 375 which align with bank terminal 315' That is tosay, the bank terminals'366 to 375 are individual to theline leading totelephone A.

Conductors 707 to 716 in Fig. 7 respectively lead to bank terminals366t0'375, in Fig, 3. Thus, conductors 707 to 71 3, in the presentassumed position or" the wipers on the shaft of switch Fare respectivelyconductively connected with bank terminals 531 to 540 of switch R. Thatis to say, conductors 7 O7 to 716 respectively correspond to bankterminals -of switch R which determine the digits 1 to 0. In the samemanner, the numerical order bank terminals 510, 527 to 530 of switch Srespectively corresponding to wipers 601, 604, 607, 701 and 704 ofswitches H to L.

It will appear presently that the call in the present instance is to beforwarded to telephone A, the number of which is 13431, and accordingly,jumpers 610 to 614 in Fig. 6 are run between the cross connectingterminals X to predetermine that the sending mechanism in Fig. 5 willnormally send a corresponding train of directive digit lmpulse serles.Thus,

' circuits can now be traced as follows: Bank set 619 to 621, jumper611, conductor 709,

bani: terminal 368 of switch F wiper 358 to bank terminal 533 of switchR; bank terminal 528 of switch S, wiper 345 of switch F, bank terminal353, wiper 607 of switch J, bank terminal 622 of set 622 to 624 jumper612, conductor 710, bank terminal 369 of switch F, wiper 359 to bankterminal 534 of switch R; bank terminal 529 of switch S, wiper 346 ofswitch F, bank terminal 354, wiper 701 of switch K, bank terminal 717 ofset 717 to 719, jumper 613, conductor 709, bank terminal 368 of switchF, wiper 358 to bank terminal 533 of switch R; bank terminal 530 ofswitch S, wiper 347 of switch F, bank terminal 355, wiper 704 of switchL, bank terminal 720 of set 7 20 to 722, jumper 614, conductor 707, bankterminal 366 of switch F, wiper 356 to bank terminal 531 of switch R.That is to say, bank terminals 510, 527, 528,529 and 530 of switch Sare, by reason of the position assumed by the wipers of switch F inseizing-the terminals corresponding to the line leading to telephone A,connected respectively to bank terminals 531, 533, 534, 533 and 5310fswitch B, remembering in this connection, that armature 506 is applyingground through wiper 509 to bank terminal 510. V

Going back to the condition wherein the relay 526 actuated responsive tothe 'wiper ice rupter 1 until the relay 541 is caused to actu- I ate.This occurs responsive to the ground 514 encountering the first groundedbank terminal, it will be clear that when the relay 526 actuates, therelay 523 by its armature 501 efliects the open impulses for directingthe extension of the connection to the line leading to telephone A. Thelatter said relay will continue to operate its armature 501 responsiveto the ground impulses from the interapplied from wiper 509 present onbank ter- .n1inal 531 being encountered by,wiper512,and

conducted over wiper 513 and engaged bank terminal to the winding ofsaid relay 541. The relay 541 locks'through its armature 542, wiper 514to the ground on its engaged bank terminal. And, in view of the factthat all the bank terminals co-operative with wiper 514, excepting theone it is shown resting upon, are permanently grounded, the relay 541will be maintained locked until the wiper 514 is returned to the drawnposition. The relay 523 will have energized onetime, to efi'ect theimpulse for the first digit 1, after relay 526 actuated until wiper 511encountered bank terminal 531 and thereby caused relay 541 to actuateand disconnect the winding of relay 526 to retract armature 502, so thatarmature 501 therefore efiected one open impulse to the relay 401 forcausing the-selector G to select an idle trunk on its first bank levelleading to second selector D ,-in the well known manner. v

r The ground derivedthrough wiper 514 is new applied through armature543 to the interrupter contact on the motor magnet 525, thelatter saidmagnet thereupon operating to restore the wipers of switch R to thedrawn normal position, the relay 541 deactuating consistent with itsslow-releasing characteristic, the latter being timed to insuresuiiicient trunk hunting time for the switches operated; the selector Gin the present instance.

At the time relay 541 actuated, ground applied through armature 545energized motor magnet 546, preparatory to causing-the wipers of switchS to advance one step responsive to the retraction of the armature 545,at which time ground applied through armature 509 will be extended tobank terminal 533. Relay 541 being deactuated,the paths from theinterrupter I to the relay 523 and motor magnet 525 are closed for theinitiation of the seconddigit series of two open impulses correspondingto the digit 3, which said series will terminate when the wiper 512encounters the latter said bank terminal 533, in the manner as describedwhen the single impulse for the first digit 1 was sent. The relay 541will operate to efi'ect the said termination of the second digit seriesand provide the space between the second and third digit series andcause the wipers or the switch S to be advanced one step preparatory tosending the third digit series of four open impulses. The secondselector D operated in the well known manner to select the first idletrunk leading to third selecter F responsive to the second digit series.

Ground applied through wiper 509 is now extended to bank terminal 534.The switch 0 idle trunk leading to connector H The wipers of switchS-are thereafter caused to advance one step preparatory to sending thefourth digit series ofthree open impulses, the wiper 509 then restingupon bank terminal 529, so that ground will now exist on bank terminal533 of switch R.

The wipers of switch It will new step. ad Vance while. the: fourth digitseries corresponding to: 3 will be sent to operate connector Hvertically in the well known manner. Thev switch will thereuponrestore-its wipers to the. drawn position and the wipers of the switch Swill be advanced one step so that Wiper 509. will bezresting on bankterminal 530 and ground till then exist on bank. terminal 531,.preparatory to the sending of the lastsingle open impulse. correspondingto digit.l.

The wipers'oi switch R will now step advance while the fifthdigitimpulse. is being sent effective to rotating the wipers of connector Hin the well known manner to seize and ring upon the line leadingtotelephone A7, in the well. known manner, after which 7 the wipers ofthe: switch R will restore. to the drawin position andrelay 5.41willdeactuate.

At the'time relay 541 deactuates. following the sending: of the openimpulse constituting the last digit 1 the wipers. or switch S will beadvanced one. step in the manner as before, this time. the ground onbank terminal 550 beingjapplied over wiper. 508, conductor 551,make-before-break spring 378 to the winding of relay 379, the lattersaid relay actuating and locking to toe grounded armature 33%, the relaydeactuating. This will cause relays 505 and 518. to deactuate.

- At this time, the line. relay in. the connector H is energized througha path involving arm'atures380 and381. and the winding of polarizedrelay 382,.in place of the armatures 50l.and 502'. The relay 382 willtilt its armature clockwise. into the. indicated Ring. p0s., however,to. no operative eflect.

It. will be notedat this time, that when the relay 323 first actuated,the. windings of the backebridge relay in connector D thereby becameconnected through bank terminals 383-384, wiper 312313, armatures 385386, make-before-break springs 387-388 and the upper and lower windingsof relay 389 to battery and ground, respectively. The backbri'dge relayin connector D and relay 389 will not actuate under the condition,because the battery on the upper winding of said backbridge. relay andthe battery on the upper winding'of relay 389 oppose.

Upon the response at telephone A, wherein the connector H will cause thedirection of current traversing the winding of relay 382 to be reversed'in direction so that the armature of the latter-said relay will betilted: counterclockwise in the indicated Ans; po's, under which"condition ground from the. armature of relay 382 will energize the relay390, causing obvious circuit changes which. will cause: the: battery on:the. upper winding of the back+bridge relay in connector D to. energizein. series with the lower winding of relay 389. inswitch- F, saidback-bridge.

relay and relay 389 actuating. The actuation of. the backbridge' relayin connector D-wlll cause. current. to be. reversed to the callingtelephone A. The talking path between the telephoneA an'd A. willinclude the condensers 391-392;-

It will. be. understoodthat. any well known or. other. suitableso-terined repeater may be introducedzinto the trunk leading-in toselector'i) from thebanksof selector G; This will. also apply to thetrunk leading-in to selector D fronithebanks ofselector E. The efiectiveoperation. will be the same as if the said repeaters were not employed,being used for translating from three wires to two wires for theinter-otlice trunk.

UaZZing party attelephonerl abandons call while call is being forwardedIf it is assumed that the calling party at telephone A abandons thecallwhile-thecall is being forwarded from the primarily called line totelephone A, it will be clear that the connector D and antecedentswitcheswill restore to normal, subject to new use. This will remove theground from conductor 7 5, so that relays 323. and 3.35 of switch. Fwill deactuatetorender said F subject to new use. Relay 505 willdeenergize responsive to the deactuationl ofv relay 335, so that relay518' will unlock. Thearmature-560 onrelay 518 will now applygroundthrough wiper 507 to cause. the. motor. magnet 5.46 to restore thewipers of. switch S to the drawn normal position. The armature'561. onrelay 518 will now-apply ground through wiper'515 to cause the motormagnet 525 to restore the wipers of switch R to the drawn position.

Encountering the: line. leading. to telephone A. busy Had the lineleading to telephone A been encountered busy, the connector H would haveapplied busy tone back over the lower talking conductor339 condenser392, audible to the. calling party at telephone A.

Releasing connection-called party. hangs up first nector D will notrelease its wipers underthe' present condition. Also, the connector HWlll not release its wipers under the present condition because the linerelay of the latter said connector is still maintained energized throughthe winding of the relay 382.

When the calling party at telephone A now hangs up his receiver, and in.view of the fact that the backbridge relay in connector D isdeactuated, the connector D will release its wipers, and the connectionfrom telephone A up to and including the connector D will be released tonormal, subject to new. use. Ground being thus removed. from-conductor75, relay 379 will deactuate and open the path including the windingxofrelay 382, so that the front-bridge relayin the connector H willdeactuate and'cause the latter said connector to release its wipers andthe antecedent selectors F J D and G,the circuits used in the call nowbeing at normal.

Releasing connectioncalling party hangs up first 7 If it is assumed thatthe calling party at telephone A hangs up first upon the termination ofthe service this will cause the line relay of connector D to deactuate,followed by the release of the antecedent switches J C B and L theconnector D remaining in seizure. When the called party at telephone Ahangs up, the current traversing the winding of relay 382 will bereversed, causing the relay 390 to deactuate to deenergize thebackbridgerelay in connector D so that the latter said relay willcleactuate to release the wipers of the latter said connector. Then theconnector D releases,ground is removed from conductor 75, so that relays323 and 379 will deactuate to open the circuit path including thewinding of relay 382 and cause the line relay in the connector H todeactuate. Since the back-bridge relay in this connector H deactuatedresponsive to the party at telephone A hanging up, the wipers ofconnector H will release, the circuits used in the call being now normaParty at telephone Am-ag change the normal prearranged setting for fanwarding call to telephone A to a random desired Zine 701 and 7 04 ofswitches I, J, K, and L, respectively.

Before the party at telephone A hung up his receiver after causing theset relay C to be actuated and locked, the said party could have changedthe setting from that to cause calls to be forwarded to telephone A ashas been described. V

' Let it be assumed that it is his desire to have calls directed to hisline leading to telephone A forwarded to a random desired line A ,'the

telephone number of which is 14321.- The party at telephone A willoperate his dial to annex the digits 1-1321, following the sending ofthe series of eleven open impulses to set the relayC.

It will be noted that under the condition of causing the relay C to beset as assumed, the relay 2will be in actuated condition while the partyat telephone A maintains his receiver off the switch-hook, so that acircuit can be traced from line terminal 81, conductor 82, attractedarmature 88, conductor 84-, upper winding of relay 725 to grounded bat.tery. Also, a circuit can be traced from terminal 85, conductor 86,attracted armature 87, conductor 88, lower winding of relay 725 toground, the latter said relay actuating. The slow-releasing relay 726actuates, energized in a local circuit of relay 725. Relay (2! thenactuates, energized in a local circuit of relay 726. 7

When the party at telephone A hangs up his receiver after setting relay0 forthwith without annexing any digits, the relay 725 will deactuate,its armature 728 applying ground through armature 729, winding ofslow-releasing relay 7 30, wiper 7 of set 731 and 732, bank terminal788, conductor 7 3th to the winding of motor magnet 625, the latter saidmagnet stepping the wipers of switch H one step from the drawn position.Relays 726 and 727 will deactuate consistent with the slow-releasingcharacteristic of relay 726.

It will be noted that wiper 705 normally grounds conductor 735 and,therefore, similarly grounds wipers 702, 608, 605 and 602. So when thewiper 602 moved-to bank terminal 628, this ground is continued overconductor 629, armature 7 37 conductor 738 to all bank terminals engagedby wiper 603 at offnormal positions. The magnet 625 will operate byinterrupter action, so tiat no upset will occur to the setting relay 0to unset the line. It will also be noted that when relay 730 actuated,its armature 7&0 applied ground to the winding of motor magnet 7 41 ofswitch M so that when relay 7 3O deactuates following the impulse sentto the motor magnet 625, the armature of the ,inotor magnet 7 41 willadvance the wipers of switch'M one step- When the relay. 727 deactuates,ground will be applied through armature 743, bank terminals co-operativewith wiper 731, interrupter armature of motor magnet 741 to the windinof the latter said motor magnet, causing it to operate and step thewipers of switch Mv around to the drawn position. i

However, in the present assumed instance, the party at telephone A doesnot hang up his receiver forthwith after setting the relay C, but on theother hand, annexes the five digits 14-321 designating the randomtelephone A for example. The sending of the digitl constituted of oneopen impulse will cause the relay 7 25150 momentarily retract armature728, so that a ground impulse will be sent from said armature 728,armature 729, winding of relay 730, wiper 732, bank terminal 733,conductor 734 to the winding of motor magnet 625, the wipers of switchHbeing stepped one step so wiper 601 will rest on bank terminal 630 whenthe armature of said motor magnet 625 retracts. The armature 740, whenretracting, will cause the op eration of the motor magnet 741 to advancethe wipers of switch M one step, so that wiper 731 will then rest on thebank terminal 745.

The sending of second digit 4 constituted of tour open impulses willcause the relay 725 to momentarily retract its armature 728 four times,so that four ground impulses will be sent from the armature 727,armature 729,

winding of relay 730, wiper 732, bank terminal 745, conductor 746 to thewinding of motor magnet 635, the wipers of switch I being therebystepped four steps so that wiper 604 will rest on bank terminal 636. Theretractionof armature 740will causethe operation of the motor magnet 741to advance the wipers of switch M one step, so wiper 732 will rest onbank terminal 747.

The sending of third digit 3 constituted of three open impulses willcause the relay 725 to momentarily retract its armature 728 three times,so that three ground impulses will be sent from the armature-728,armature 729, winding of relay 730, wiper 732, bank terminal 747,conductor 748 tothe winding of motor magnet 645, the wipers of switch Jbeing thereby stepped three steps so that wiper 607 will rest on bankterminal 646. The retraction of armature 740 will cause the operation ofthe motor magnet 645 to advance the wipers of switch M one step so thatwiper 732 will rest on bank terminal 750.

The sending of fourth digit 2 constituted oitwo open impulses will causethe relay 725 to momentarily retract its armature 728 two times, so thattwo ground impulses will be sent from armature 728, armature 729,winding of relay 7 30, wiper 7 32, bank terminal 750, conductor 751 tothe winding of motor magnet 55, the wipers of switch K being therebystepped two steps so that wiper 701 will rest on bank terminal 756. Theretraction of ar mature 740 will cause the operation of the motor magnet741 to advance the wipers of switch M one step so wiper 732 will rest inbank terminal 757.

- The sending of the fifth digit 1 constituted of one open impulse willcause the relay 725 to momentarily retract its armature 728 one time sothat one ground impulse will be sent from armature 728, armature 7 29,windof relay 730, wiper 7 32, bank terminal 757, conductor 758 to thewinding of motor magnet 765, the wipers of switch L bein thereby steppedone step. so wiper 704 will rest on bank terminal 766'; The retractionon armature 740 will cause; the: operation: 01% the motor magnet 741 toadvance the wipers of switch. M one step, so wiper7-32 Willi restonbank. terminal; 7.67. v

I twill: be noted! that under the lastv toregoing conditionthe bank.terminals 510, 527, 528, 529' and 530 cooperative with wiper 509' arenow connectedthrough wipers 601, 604, 607 7 01 and 704 overobvious,circuitpathszto terniir is 531, 534 533,532, and531,respectively. Under thiscondition, it. will be. clear in view ofprevious descriptions, that. the" sending, mechanism will be set to sendthe. train of. digits 1.-432.1 responsive. to the germinals 7110.73being seized by connector In this connection, it will. be understoodthat although thejumpers. 6l1to 6I4set the sending mechanism to send thedigits. 13 4--31 corresponding. to: the.- telephone. number oftelephoneA,when the. wipers-601,604,, 607,. 701, and. 7 0.4. are. intheir. drawnv normal. positions, this. sameset-up may be attained bydirectively setting the latter said wipers. on. the co-operative; bankpositions corresponding to digits 134'-3-1,. respectively- That istosay, it is not necessary to have the. jumpers 611 to=614', butto do awaywith them will make it necessary to: always directiively set not onlyrelay O.',.but also the. switcheslzl to L in accordance with. atelephone number.

Upon the party at telephone. A hanging up his receiver, relays 24, 725,726 and 727 will deactuate; also, the relay 212, the windings of whichhave been in multiple with the wintc lings of relay 725. The wiper 705being off the bank terminal 721 it is drawn resting on and is resting onbank terminal 770', when relay 727 deactuates there will be no groundapplied through the armatures of this relay from wiper 705, so thewipers of the switches. H toL will not be restored at this-time.However, when armature 743 retracts, it causes the wipers of switch M torestore. to the drawn position by interrupter action of its motor magnet7 41'.

It will appear presently that responsive to. relay 725deactuating;,relay 93 will actuate and cause the lower winding of relay302 to energize. This operation is only momentary and will not upset theintended operation. Ordinarily, the party setting relay C and theswitches H to L will not hang up hisreceiver: at this time, but: willoperate the dial, as will appear presently, to cause a test to be madeof the setting by causing the impulse sending device to send impulsescorresponding to the setting tooperate the switches to extend aconnection from-the calling line to the called line-corresponding to thesetting; He will then hang up his receiver; Of'course, moving bankterminal 767 onestep to the lett, making it necessaryto anneXLtwo digitseries:

1; only part of'switehes H to L are set they will restore Inthisconnection, it will be notedthat if r the party at telephone A, whensetting the relay C.

switches H to L had failed to set all of the latter said switches, byleaving off one or more of the five digits, the wiper 705 would then bein the drawn position. So when the relay 7'27 deactuates responsive tothe hanging up of the receiver of telephone A, this ground on wiper 705would be applied through bank terminal 721 and through those of thewipers 602, 605, 608 and 702 as are in ofl'-normal position in multiple,to conductor 629, and through the multipled armatures on said relay 727to the resting contacts cooperative with the armatures on the motormagnets of the switches H to K which are offnormal, to restore theseswitches to the drawn positions, the switch M restoring in the mannerbefore described fromarmature 743. Under this condition any callsdirected to the line leading to telephone A will be forwarded totelephone A in accordance with the settings of the'switches H to L whenin the drawn positions, since only relay C will-be set.

U nsetting the relay 0' and the switches H to L When the party attelephone A desires to unset his line for forwarding calls directedthereto, he will remove his receiver as if to initiate a call, andthereupon operate his calling device oial in accordance with thefingerhold Y used in sending a series of twelve open impulses. Thiswillcause the relay 31 to operate in the manner before described tounlatch the catch 36 to release the springs of armatures on relay 727,through the interrupter contacts of the motor magnets of switches H to Lto restore said switches to the drawn positions, thus efi'acingthe spe--cially set up condition of the switches H to L.

The switches H to L (with the exception of switch H, which has a twelfthbank terminal, as will appear presently) are each drawn with five setsof bank terminals. In a commercial embodimentthere would-be eleven suchsets; a normal position set and one position for each digit from 1 to 0.

The five switches H to L contemplate a train of five digit series. Itwill be clear that more switches may be added to increase this range,the switch M having corresponding bank positions. added.

Ground will now be applied through spring 90, conductor 91, multipledParty at telephone A after causing relay 0 to be set may hang up hisreceiver and initiate a new calll and by his dial direct the call to thennmberof his own line The'connector D (or any other connector of thegroup containing connector D) and switch F will operate in the mannerdescribed from telephone A to cause the call to be extended to thetelephone predetermined by the said setting of relay C; The same willapply if the switches, H to L are set for eX- tending calls to arandomdesired line. The foregoing has in View that the line leading totelephone A is clear of the bank terminals accessible from connector Dwhen the set relay C is in the set condition.

Party at telephone A after causing relay 0 andthe switches H to L to heset may thereupon cause the call to be extended to the random desiredline If the party at telephone A desires to verify the set conditionafter causing the relay C and the switches H to L to be set forforwarding calls to a random telephone A he may, without first hangingup his receiver, operate his dial in accordance with the finger-hold Zand thereby send a series of eleven open impulses to cause the call tobe extended to the line indexed by the set condition of the switches Hto L, which in the present assumed instance is to telephone A The relay24 underthe present assumed condition, is still actuated and energizedfrom armature 22. Thus, the relay 725 will momentarily retract itsarmature 728 eleven times and send a corresponding number of groundimpulses through armature 729, winding of relay 730, wiper 732, bankterminal 7 67 (it having stepped to the latter said terminal followingthe setting of the switch L), conductor 771 to the winding of relay 93,the latter said relay actuating and locking to release trunk conductor27 responsive to the first impulse of said series.

Armature 9d closes the grounded Winding of relay 95 to conductor 75, sothat the lower winding of relay 302 will energize in series with thewinding of relay 95. Slowreleasing relay 96 will be operativelyenergized in a local circuit of relay 95. Relay 302 will operativelyattract only its armature 306 from its resting contact to its makecontact in the manneras when connector D ap: plied ground over conductor75. The finder switch F or one of its group will operate to hunt for andseize the bank terminals correspondingto the line leading to telephoneA. When this latter line is found and relay'323 actuates, ground fromarmature 321 is applied through wiper 311 to conductor 75 as beforedescribed. This latter ground will deconductors 202 and 2?.

look.

. when energize the winding ofrelay '95 and it Will therefore deactuate,followed by relay 96.

After relay v95 ,deactuates and'until relay 96 deactuates, ground isapplied through armatures 97 and 98 to thewinding of relay 99, thelatter said relay actuating and locking to conductor 75. iii-matures 101and 102 disconnect the line conductors leading from the telephone A tothe line switch B, so that relay-212 will eactuate to remove ground fromRelay 93 will un- Responsive to relay 99 actuating, the windings ofrelay 389 will energize in series with telephone A, the receiver ofwhich is ofi the switch-hook. The armature of relay 289 will applyground to wiper 311 and conductor i to maintain the relay 99 locked.

Responsive to the actuation of relay 99 the relay 212 will deactuate toremovethe ground from conductor 202 so that the relay 28 of the lineswitch B will deactuate and first selector E will restore to normal inthe obvious manner. Relay 21 will deenergize and relay 24 will deactuateresponsive to relay 28 deactuating.

It will be noted, in this connection, that when relay 2% is actuated,the private bank then resting upon the bank. terminal 315, it

will be clear that the relays 323 and 335 thereupon actuate 1n themanner before described. This latter operation will cause the impulsesending mechanism in Fig. 5 to transmit a train or digit series toprogress the call to telephone i 2 in accordance with the settings ofswitches H to L in the manner as before described, he connector Gapplying ringing current to the line leading to telephone A Relay 335deactuates and relay 3T9 actuates.

Current derived through the windings of the relay 389 traverses thetelephone A in the same direction aswhen it derived current from thewindings or relay 212. However, the party at telephone A removes iisreceiver irom'the switch-hook in responding, the arn'iature of relay 382will tilt into the indicated Ans. pos. and cause the relay 390 toactuate for reversing the direction of current applied through telephoneA. This reversing of current direction is for operating supervisorydevices, call meters and prepayment :coin collecting apparatus..Moreover, the reversal .eliective to relay 382 may be caused byreversing apparatus located intermediate of switch F and connector G andoperated message timing apparatus. The said supervisory devices, callmeters and .prepayment coin collecting apparatus, and the said reversingapparatus has not been shown, since. such hasbeen disclosed inapplications of applicant filed heretofore. Moreover, thisv reversingapparatus may be included in a well known Bunk impulse repeater "locatedintermediate of the switches F and The party at telephone A is now intalking relation with the patty at telephonefA At the time relay 99actuated andlocked and selector E restored its wipers and "relay 24deactuated, relays '725, 7216 and '727 deactuated, causing switch 'M tobe restored to the drawn position in the manner before described.

Release of COMBGtiOik-CCblld party hangs up first If it is assumed thatthecalled party at telephoneoA hangs up first upon the termination ofthe conversation, this will reverse the direction of current traversingthe winding of relay 382, causing the relay 390120 Ideactuate andrestore the direction of current traversing the telephone A. Theconnector G will not release its wipers under the condition, since thewindings of its line relay are still in series with the winding of relay382. However, when the party at telephone A hangs .up :and deenergizesthe relay 3-89, the relay 99 will be thereby unlocked, since ground willthen be removed from conductor 75. This also causes irel'ays323 and 3.79 to deactuate. This restores .the condition of switch F .to normal andopens the energizing path for the hue relay of connector G so thattheconnector-Gtand antecedent switches release to normal. However, relay(1 and switches H to L are in their set .positiomand this latter hasbeen verified by ltheresponse of the ,party at telephone A Y Release of-00nne0ti0wcalling party hangs "up first If it .is assumed that thecalling party at telephone A hangs up first upon "the termination oftheconversation, this will deenergize the relay 389 so that relay 99 willunlock and remove the ground from conductor 7 5, causingrelays"323,'379and390 to deactuate and open the energizing circuit forthe line relay of connector G The switches antecedent to said connectorwill release, but

the said connector will remain in seizure. .vhen the party [at telephoneA hangs up, connector G willrelease its wipers. However, relay C andswitches H to L are in thei set position. I

